Vacuum tensioning of paper in a high speed printer



July 5, 1966 c. l. WASSERMANN VACUUM TENSIONING OF PAPER IN A HIGH SPEEDPRINTER 2 Sheets-Sheet 1 Filed March 9, 1964 W :L/ flw, 0 B 6 f 4 I 1 l1 l l T 1 l W HI w,v\\ A 9 m H l INVENTOR. 04m. 1 mssm Mn/v/v FIG.

ATTORNEY y 5, 1966 c. l. WASSERMANN 3,

VACUUM TENSIONING OF PAPER IN A HIGH SPEED PRINTER Filed March 9, 196 2Sheets-Sheet 2 FIG. 2

BYWZ/(JIM/ ATTORNEY United States Patent 3,259,288 VACUUM TENSIONING OFPAPER IN A HIGH SPEED PRINTER Carl I. Wassermann, Queens Village, N.Y.,assignor to Datamark, Inc., Westbury, N.Y., a corporation of New YorkFiled Mar. 9, 1964, Ser. No. 350,242

8 Claims. (Cl. 226-60) The present invention concerns paper handlingand, in particular, methods of and means for improving tensioning insprocket transported high speed printer paper handling.

The present invention is particularly concerned with, although notlimited to, that type of printing device .having a continuously rotatingtypewheel cooperating with printing hammers. The paper is fed betweenthe typewheel and the hammers, and at appropriate times the severalhammers are independently actuated to print the different charactersinvolved. This arrangement is now well known in the art as a means forprinting the output of an electronic computer. While such printers arein wide use, many problems still remain unsolved. In addition, manyoperating characteristics of such printers are in great need ofimprovement. Furthermore, more stringent requirements are being made as,for example, greater speed of operation and greater reliability areconstantly being sought. The handling of the paper to be printed upon isone of the constant problems in high speed printers. Problems connectedwith paper feeding include handling paper of various widths, handlingpaper of various thickness properly tensioning the paper, starting andstopping the paper motion without jitter or tearing, etc. Some attemptshave been made to solve these problems by means of complicatedmechanisms requiring tedious and repeated adjustments. The presentinvention provides methods of and means for solving these problems in asimple manner and with a resulting mechanism which is simple to use,inexpensive to build, and which has a long life expectance of reliableoperation.

Going into detail, the paper used on the machines which are the subjectof the present invention is provided with equally spaced sprocket holesalong its two edges. This paper is moved past the printing area by meansof two sets of toothed sprockets. In order to provide increased tractionwith the paper to prevent tearing at high speed, these sprocket teethmay be mounted on flexible chain links and directed to travel with thepaper over a distance equal to several times the spacing betweenadjacent sprocket holes. In the usual arrangement one set of sprocketspulls the paper While the other set acts as a follower holding the paperback suiiiciently to provide the required tension on the paper acrossthe marking area. Difiiculty arises, however, with this system for anumber of reasons. The paper is easily torn at the sprocket holes if thetracking of the follower sprockets is not substantially perfect. Complexmeans have been devised and much time has been required in set-up andduring operation to phase the sprockets and to provide optimum papertension.

It has been found in accordance with the present invention that a simplevacuum device can be used to tension the paper and to eliminate the needfor phasing means. Not only is the operation of the printer greatlysimplified but its operating characteristics are greatly improved.Starting and stopping the paper is smoother. Wear on the sprocket teethis reduced. Tensioning can be easily and accurately controlled.

Accordingly, one object of the present invention is to provide methodsof and means for handling paper in Patented July 5, 1966 ice high speedprinters which is simple and less expensive than previously and yieldsimproved handling characteristics.

Another object is to simplify loading and to eliminate the need fordelicate and time consuming adjustments of paper tension and sprocketphasing hitherto required.

Still another object is to provide for changes in paper dimensions suchas those due to humidity eifects causing changes in tension due toelongation of sprocket holes.

A further object is to improve transient response by a substantiallyinertialess tensioning system providing wide-band response.

These and other objects will 'be apparent from the detailed descriptionof the invention given in connection with the various figures of thedrawings.

In the drawing:

FIGURE 1 is diagrammatic side view of a printer and paper feed system inaccordance with the present invention.

FIGURE 2 is a perspective view of the vacuum chamber used in the systemof FIG. 1.

FIG. 1 shows a perforated paper 1 which is driven by sprocket teeth 3carried by a sprocket chain 2. The sprocket chain 2 in turn is driven bya toothed sprocket 4 on shaft 5 turned by a suitable means not shown.Sprocket chain or belt 2 is supported in a predetermined elliptical pathby idler sprocket 7. While not shown, it will be understood that asecond set of sprockets and a sprocket chain similar to the one justdescribed are provided for the far edge of the paper. These sprocketsand chains make up the driving pair. I

The follower means is made up of sprockets 9 and 1 and chain or belt 11carrying teeth 12 together with a similar set, not shown, at the faredge of the paper. This second pair is slave driven in synchronism fromthe first drive sprockets by a suitable belt or chain not shown.

Printing on the paper 1 is accomplished by suitable means such ascontinuously rotating type drum 13 carrying a great plurality of typefaces 18 and hammer 17 actuated by suitable driving means, not shown, toprint by pressing paper 1 against preselected type faces 18 throughinked ribbon 14. Ribbon 14 is moved between rollers 15 and 16 bysuitable means,not shown. Auxiliary tensioning is provided by means of avacuum drawn in chamber 19 extending at least across the width of thepaper 1. Vacuum in chamber 19 is produced by a suitable motor 21 drivingfan 6. Suction from fan 6 to chamber 19 is accomplished over tube 8. Thedegree of tensioning provided by the vacuum drawn against the paper 1may be controlled by varying the degree of vacuum in chamber 19. Onesimple manner of controlling the degree of the vacuum is to control thespeed of the motor 21 as by means of a variable auto-transformer 28having a movable tap 29 and connected to motor 21 over leads 26-27 andto a suitable source of alternating current by means of plug 32 andleads 3031.

FIG. 2 is a perspective view showing details of the vacuum chamberbriefly described above. The sides of the chamber have been omitted inorder to permit a better view of certain features. The suction pipe 8couples to the rear of the vacuum chamber as by a flared extension 36.Between extension 36 and the inside of the vacuum chamber itself areprovided a plurality of port holes 25 provided with adjustable shutters24 for auxiliary control of the vacuum within the chamber and forshutting off air flow beyond the edges of the paper. In order to adaptthe chamber readily to various paper widths, adjustable end plates 22and 23 are provided. This adjustment for paper width is automatic sinceend plates 22 and 23 are carried by brackets 38' and 38 attached totractors 11 and 11 respectively. Thus, when the tractors are adjustedalong their supporting rods 34 and 35 in order to match the tors are soadjusted.

desired paper width, the vacuum chamber is automatically adjusted to acorresponding width. Felt pads 37 and 37 may be provided to provide aflexible seal to the vacuum chamber regardless of its width adjustment.In order to maintain the proper tractor separation and at the same timevacuum chamber width, locking means such as thumb screws 39 and 40 areprovided for longitudinally positioning and locking tractors 11 and 11to shaft 34.

It will be appreciated that the tensioning of the paper by the vacuummeans described above provides substantially inertialess tensioning.This has the effect of raising the cut-off frequency of the equivalentmechanical circuit and thus provides a wide-band response. Also, sincethe vacuum chamber end plates are attached by means of brackets to thetractors, the chamber width is automatically adjusted for paper widthwhen the trac- In fact loading of the paper and the optimum adjustmentof tension, in the present system, is greatly simplified over systemshitherto available.

While only one form of the present invention has been shown anddescribed, many modifications will be apparent to those skilled in theart and within the spirit and scope of the invention as set forth inparticular in the appended claims.

What is claimed is:

1. In a high speed printer, the combination of, paper pulling means, atleast two paper follower means one for each edge of the paper, means formaintaining predetermined separation between follower means inaccordance with the width of paper to be accommodated, vacuum tensioningmeans extending across the path of said paper between said pulling meansand said follower means, and laterally adjustable means for determiningthe effective width of said vacuum means across said paper path.

2. High speed printing means as set forth in claim 1 and including meansfor varying the pull of said vacuum tensioning means.

3. High speed printing means as set forth in claim 1 wherein said vacuumtensioning means includes a motor driven fan and a speed control meansfor said motor.

4. High speed printing means as set forth in claim 1 wherein said vacuumtensioning means includes adjustable ports for adjusting the pullexerted upon said paper by said vacuum.

5. High speed printing means as set forth in claiml wherein said vacuumwidth determining means are coupled to said follower means.

6. In a high speed printer, the combination of, at least two sprocketedpaper pulling means, at least two laterally spaced sprocketed paperfollower means adjustable to accommodate paper of different widths,vacuum tensioning means between said pulling means and said followermeans, and means for automatically adapting said vacuum tensioning meansto a given paper width inresponse to paper width setting of saidfollower mean-s.

7. High speed printing means as set forth in claim 6 and including meansfor controlling said vacuum comprising an adjustable speed motor drivenfan.

8. In a high speed printer, the combination of, at least two sprocketsfor pulling paper to be printed upon, at least two sprocketed paperfollowers, means for main: taining predetermined lateral separationbetween said followers in accordance with the width of said paper,vacuum tensioning means extending across the path of said paper andlocated between said pulling means and said follower means, and meansfor confining the effective width of said vacuum means across the widthof said paper in order to optimize tensioning paper of different widths.

References Qited by the Examiner UNITED STATES PATENTS 2,397,183 3/1946Kilgore 230l2 X 2,595,325 5/1952 Baumgartner 226199 X 2,816,757 12/1957Burkhart 226--95 3,114,491 12/1963 Wright 226 3,151,796 10/1964Lipschutz 22697 M. HENSON WOOD, JR., Primary Examiner.

ROBERT E. REEVES, Examiner.

R. A. SCHACHER, Assistant Examiner.

1. IN A HIGH SPEED PRINTER, THE COMBINTION OF, PAPER PULLING MEANS, ATLEAST TWO PAPER FOLLOWER MEANS ONE FOR EACH EDGE OF THE PAPER, MEANS FORMAINTAINING PREDETERMINED SEPARATION BETWEEN FOLLOWER MEANS INACCORDANCE WITH THE WIDTH OF PAPER TO BE ACCOMMODATED, VACUUM TENSIONINGMEANS EXTENDING ACROSS THE PATH OF SAID PAPER BETWEEN SAID PULLING MEANSAND SAID FOLLOWER MEANS, AND LATERALLY ADJUSTABLE MEANS FOR DETERMININGTHE EFFECTIVE WIDTH OF SAID VACUUM MEANS ACROSS SAID PAPER PATH.